OK, I got an answer outside this group from Magic Butter's guru. Here's what they said;
"DECARBOXYLATION:
Preheat your oven to 250°F with an oven thermometer inside. If the thermometer reads above or below 250°F, adjust your oven setting accordingly until the temperature is a steady 250°.
Place your botanicals in a baking (rotisserie) bag or covered baking dish.
Close tightly; if using a baking bag, do not puncture.
Bake for 30 minutes.
Remove your container from the oven. Let it cool for about 2 minutes before placing it, unopened, in the freezer for 30 minutes. (This step is intended to preserve certain phytonutrients.)
When time is up, your sample is ready to use.
Chef’s Notes:
To maximize THC, bake at 250°F for 30 minutes.
To maximize CBD, bake at 275°F for 60 minutes.
To maximize CBN (e.g., for insomnia), bake at 300°F for 90 minutes.
As for the amount of material left behind after straining, you can use other items to strain such as a coffee filter or cheesecloth to have a more clarified final result. We also sell smaller micron purify filter bags on our website, I have included a link to the product below."
Interesting that they like higher temps and longer times as well. Perhaps the covering slows the process. Also I know they want botanicals pre-ground before placing in the oven bag and into the oven. I compromise here by breaking bud up before and grinding after because it's so much easier to grind when it's dry. Also, spread material out after placing in the bag and on baking sheet with the palm of your hand so it is even depth, no piles.
Since I grow for high CBD content I'm going to try both the THC and CBD methods and try the results. Since this years harvest was so plentiful, (there's plenty to experiment with) I will also try some with the CBN method to see what that does for insomnia. I will report back.